<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2016, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2016, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT	MIT License
 * @link    https://codeigniter.com
 * @since    Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * MySQL Forge Class
 *
 * @category    Database
 * @author        EllisLab Dev Team
 * @link        https://codeigniter.com/user_guide/database/
 */
class CI_DB_mysql_forge extends CI_DB_forge
{

    /**
     * CREATE DATABASE statement
     *
     * @var    string
     */
    protected $_create_database = 'CREATE DATABASE %s CHARACTER SET %s COLLATE %s';

    /**
     * CREATE TABLE keys flag
     *
     * Whether table keys are created from within the
     * CREATE TABLE statement.
     *
     * @var    bool
     */
    protected $_create_table_keys = TRUE;

    /**
     * UNSIGNED support
     *
     * @var    array
     */
    protected $_unsigned = array(
        'TINYINT',
        'SMALLINT',
        'MEDIUMINT',
        'INT',
        'INTEGER',
        'BIGINT',
        'REAL',
        'DOUBLE',
        'DOUBLE PRECISION',
        'FLOAT',
        'DECIMAL',
        'NUMERIC'
    );

    /**
     * NULL value representation in CREATE/ALTER TABLE statements
     *
     * @var    string
     */
    protected $_null = 'NULL';

    // --------------------------------------------------------------------

    /**
     * CREATE TABLE attributes
     *
     * @param    array $attributes Associative array of table attributes
     * @return    string
     */
    protected function _create_table_attr($attributes)
    {
        $sql = '';

        foreach (array_keys($attributes) as $key) {
            if (is_string($key)) {
                $sql .= ' ' . strtoupper($key) . ' = ' . $attributes[$key];
            }
        }

        if (!empty($this->db->char_set) && !strpos($sql, 'CHARACTER SET') && !strpos($sql, 'CHARSET')) {
            $sql .= ' DEFAULT CHARACTER SET = ' . $this->db->char_set;
        }

        if (!empty($this->db->dbcollat) && !strpos($sql, 'COLLATE')) {
            $sql .= ' COLLATE = ' . $this->db->dbcollat;
        }

        return $sql;
    }

    // --------------------------------------------------------------------

    /**
     * ALTER TABLE
     *
     * @param    string $alter_type ALTER type
     * @param    string $table Table name
     * @param    mixed $field Column definition
     * @return    string|string[]
     */
    protected function _alter_table($alter_type, $table, $field)
    {
        if ($alter_type === 'DROP') {
            return parent::_alter_table($alter_type, $table, $field);
        }

        $sql = 'ALTER TABLE ' . $this->db->escape_identifiers($table);
        for ($i = 0, $c = count($field); $i < $c; $i++) {
            if ($field[$i]['_literal'] !== FALSE) {
                $field[$i] = ($alter_type === 'ADD')
                    ? "\n\tADD " . $field[$i]['_literal']
                    : "\n\tMODIFY " . $field[$i]['_literal'];
            } else {
                if ($alter_type === 'ADD') {
                    $field[$i]['_literal'] = "\n\tADD ";
                } else {
                    $field[$i]['_literal'] = empty($field[$i]['new_name']) ? "\n\tMODIFY " : "\n\tCHANGE ";
                }

                $field[$i] = $field[$i]['_literal'] . $this->_process_column($field[$i]);
            }
        }

        return array($sql . implode(',', $field));
    }

    // --------------------------------------------------------------------

    /**
     * Process column
     *
     * @param    array $field
     * @return    string
     */
    protected function _process_column($field)
    {
        $extra_clause = isset($field['after'])
            ? ' AFTER ' . $this->db->escape_identifiers($field['after']) : '';

        if (empty($extra_clause) && isset($field['first']) && $field['first'] === TRUE) {
            $extra_clause = ' FIRST';
        }


        return $this->db->escape_identifiers($field['name'])
        . (empty($field['new_name']) ? '' : ' ' . $this->db->escape_identifiers($field['new_name']))
        . ' ' . $field['type'] . $field['length']
        . $field['unsigned']
        . $field['null']
        . $field['default']
        . $field['auto_increment']
        . $field['unique']
        . (empty($field['comment']) ? '' : ' COMMENT ' . $field['comment'])
        . $extra_clause;
    }

    // --------------------------------------------------------------------

    /**
     * Process indexes
     *
     * @param    string $table (ignored)
     * @return    string
     */
    protected function _process_indexes($table)
    {
        $sql = '';

        for ($i = 0, $c = count($this->keys); $i < $c; $i++) {
            if (is_array($this->keys[$i])) {
                for ($i2 = 0, $c2 = count($this->keys[$i]); $i2 < $c2; $i2++) {
                    if (!isset($this->fields[$this->keys[$i][$i2]])) {
                        unset($this->keys[$i][$i2]);
                        continue;
                    }
                }
            } elseif (!isset($this->fields[$this->keys[$i]])) {
                unset($this->keys[$i]);
                continue;
            }

            is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);

            $sql .= ",\n\tKEY " . $this->db->escape_identifiers(implode('_', $this->keys[$i]))
                . ' (' . implode(', ', $this->db->escape_identifiers($this->keys[$i])) . ')';
        }

        $this->keys = array();

        return $sql;
    }

}
